Method of drawing tubes



March 12, 1935.

4. HEDDON METHOD OF DRAWING TUBES Filed Dec. 29, 1953 Patented Mar. l2,1935 I I UNITED STATES PATENT OFFICE LIETHOD OF DRAWING TUBES JohnHeddon, Dowagiac, Micln, assignor to James Heddons Sons, Dowagiac, Mich,a corporation of Michigan Application December 29, 1933, Serial 704375 RS S U E D 1 Claim. (Cl. 80-62) The method of the present invention isdethe tip joint, which is objectionable, in that it signed primarily tomeet the requirements in results in a piling up of the strain at thatpoint, the tapering of drawn tubular fishing rods, alwith the resultantliability of breakage. These though the principles involved areapplicable considerations are of particular importance in 5 to thedrawing of tubular steel golf shafts or such a light anddelicateinstrument as a fly 5 the like or other shafts in which it is desirableto rod, although they are of" lesser importance in produce a tubularshaft having a certain prethe case of short bait casting rods.determined ratio between wall thickness and The method of the presentinvention is detaper, and particularly in cases in which it is signed toconform to the above considerations essential in the taper productthatthe wall thickand to permit the distribution of the metal in 10 nessat the end of lesser diameter shall not be ratio to taper to be computedwith precision, so in excess of the wall thickness at the end of that bythe use of the present invention, fly rods greater diameter. of theutmost delicacy can be manufactured which The taper drawing of a tubehas the effect of will have all of the lightness and feel of the finerredistributing the metal and crowding it toward bamboo castmg rods andat the same time will 15 the end of lesser diameter, with the resultthat possess greater elements of strength and duraduring the taperingoperation the thickness of bility. I the walls of the tube will beprogressively in- The method of the present invention maybe creased asthe external diameter of the tube is practiced with machines orappliances of the progressively decreased, with the result that ifcharacter particularly set forth and described in 20 the intendedproduct, such for instance as a the Barnhart patent, No. 1,711,825issued May 7, fishing rod, is drawn from a tube of uniform diam-.- 1929,so that it is not deemed necessary herein to star and uniform wallthickness, the completed describe the mechanism in detail, althoughrefrod or the like will progressively increase in wall erence is had tothe accompany drawing, wherethickness toward the tip end, so that theratio in, of weight to diameter will be greater in the tip Figure 1 is adiagrammatic sectional represenof the rod than in the butt of the rod,which is tation of a tube passing through drawing rollers objectionablein the designing of certain types at the beginning of the drawingoperation; of fishing rods, and particularly in the designing Fig. 2 isa view showing a completed tube in of light rods intended for flycasting. which the drawing operation results in a contin-' 30 In thecase of a fiy casting rod, or other rods nous taper with progressivedecrease in wall in which the question of balance or feel is thicknessthroughout; and v of primary importance, it is desirable that the Fig. 3is a similar view in which the drawing wall thickness toward the tip endshall prooperation results in a tube having uniform taper gressivelydecrease as the exterior-diameter deand uniform wall thicknessthroughout. 35 creases, or in any event that it shall not increase Itwill be understood that the present drawing as compared with the wallthickness at the is intended merely as. diagrams, and that the butt endof the rod. In such rods the tip lightwall thickness and ratio of lengthto diameter ness should be in direct proportion to the (11- isdiagrammatically indicated rather than illuslO mension of the-diameter,and such lightness of trated, in order to better bring out theprinciples tip is particularly desirable on relatively long of thepresent invention.

rods of the fly casting type, since an increase in In practicing themethod of the present inwall thickness toward the tip will so distributevention, I first start with a tube A of uniform the metal as to impart afeeling of tip heaviness exterior diameter, but tapered on the interiorto the rod in the hands of an expert user. Such in order to provide aprogressively decreasing considerations, of course, do not apply tocertain wall thickness from' the prospective butt end more rugged typesof rod, in which an increase of the rod toward the prospective tip end.For in strength toward the tip end is peculiarly depurposes ofillustration, it may be assumed that sirable rather than delicacy in thedistribution the tube in question; at the thicker end, possesses 0 f Wht. a wall thickness of .010 in. and at the opposite 50 Furthermore, ithas been found that in the end a thickness of .005 in., and the initiallength testing of fly rods that an increase of the wall of the tubewill, of course, be such as to permit thickness in the tip region of therod has a of its being drawn to the intended length of a tendency tothrow an unequal load or strain fishing rod or the like of the intendedweight toward the larger and thinner walled end of in the completed rodor rod section.

The tube in its initial form, having uniform exterior diameter andinterior taper, is of a character which is being produced at the presenttime by tube drawing mills in conformity with well understoodprinciples, but the subsequent drawing of the tube to produce a fishingrod of the character previously described is in conformity with theprinciples of the present invention.

In the tapering operation now to be described, a tube of uniformdiameter and interior taper is introduced between rolls B keyed uponshafts C, each roll being provided with a progressively deepening grooveD, the formation of the groove being computed to impart the desiredprogressive taper to the tube in ratio to the speed of advance of thetube through the rolls. Such taper may be uniform throughout or computedin varying ratio within different portions of the tube, or some portionsof the tube may be tapered and other portions uniform, depending uponthe depth of. the roller groove around different portions of itsperiphery, in conformity withthe principles set forth and described inthe Barnhart patent, No. 1,711,825.

In advancing the tube through the rolls, the tube is drawn forward by acomealong or the like, which is operated in timed relation to therotation of the rolls which preferably rotate in opposite relation tothe advance of the tube, as indicated by the arrows in Figure 1, so thatthe exterior taper imparted to the tube will at all times be determinedby the configuration of the roll grooves in ratio to the speed ofadvance of the tube relatively to the rotation of the rolls.

As the tube advances under the drag of the comealong, the metal will bedrawn back or crowded rearwardly as the tube is elongated, and the wallthickness will be progressively increased during the operation, with theresult that after the tube has been drawn into the form of a rod sectionor the like, the desired exterior taper will be secured in conjunctionwith the'desired ratio of wall thickness, so that by starting with aninitial wall thickness less than the intended resultant wall thicknessin the reduced end of the rod, it is possible to build up the wallthickness to the desired degree, which may be less than or equal to thewall thickness at the opposite end of the larger diameter, which latterend may retain its initial wall thickness and diameter in the completedrod. The present process may also, if desired, be employed to provide anincreased resultant wall thickness at the end of lesser diameter,although the present invention is designed primarily for use in thosecases in which it is desired to decrease the wall thickness concurrentlywith decrease in ex- ,terior diameter. I

In Fig. 2 I have diagrammatically indicated a rod section having aresultant wall diameter of .010 in. at the butt end and .007 in. at thetip end; and in Fig. 3, a rod section in which the resultant wallthickness is the same-.010 at each end of the section.

In tapering the tube, beginning at the heavy end, it will be understoodthat I drag less metal as the taper progresses and the tube is elongatedin the tapering process, which fact permits of a redistribution of themetal in such a way as to produce uniform wall thickness throughout, ora thinner wall at the end of smaller diameter as compared with the wallthickness at the end of larger diameter, thereby imparting extremeflexibility and lightness in the tip region.

Another feature of importance in connection with the present inventioninvolves the provision of greater strength at or near the ends of thejoint where the ferrules are located and which are the points ofincreased liability to breakage due to the fact that the rod is madeinflexible by the natural stiffness or resistance of the ferrules, whichprevent a symmetrical yielding or bending of the rod over its entirelength when the rod is under strain. This circumstance indicates thatthe symmetrical resistance to strains should not be less but preferablymore immediately adjacent to the ferrules.

Thus by employment of the present invention, it is found that a tubehaving a wall thickness of .010 in. at one end may be employed, whileformerly, by conventional methods of drawing, it was necessary to employa tube having a lesser thickness of .007 in., which limitation in thepast was due to the fact that the use of a thicker tube would result inan objectionably heavy tip joint as a whole.

By the use of the present invention, a tube which initially varies inwall thickness from .010 in. down to .005 in. may be tapered in such away that the weight of the section as a whole will, when completed, beno greater than a tube drawn from a tube having an initial wallthickness of .007 in. throughout its entire length. In other words,without increasing the weight of the section as a whole, it is possibleto start with a wall thickness of .010 in. at the end of larger diameterwhere strength is most required, and at the same time secure the desireddistribution of wall thickness and weight throughout the entire lengthof the rod section. This is a very important result, since it is con--ducive to a proper distribution of resistance to strain either in a finefly rod or in an extreme- 1y flight, flexible and long bait casting rod.

Although the invention has been described with particular reference tothe requirements of fishing rods, it is not the intention to limit its'use thereto, since other tubular products may be drawn and tapered inaccordance with the principles of the present invention.

I claim:

The method of fabricating a flexible metallic tubular structure, whichconsists in first producing a tube having a uniform external diameterand tapered on the interior to afford a tapering wall thickness and inthereafter advancing the tube through dies with a resultant elongationand redistribution of the metal to afford an exterior taper byprogressive reduction of the exterior diameter toward the end initiallyhaving the lesser wall thickness and a progressive increase in wallthickness toward the end whose exterior diameter is being reduced ascompared with the initial wall thickness of the corresponding region.

' JOHN HEDDON.

